Introduction to XPath

The basic path expression syntax is similar in style to file-system addressing. If the path starts with the slash ( / ), then it represents an absolute path to the required element. Only the / represents the root element. For the example above, the expression "/" represents <bookstore>. To get all the <book> elements use: 

/book

This will return both <book> elements. To get the <price> elements use:

 /book/price

<bookstore>
  <book>
    <title id='1'>XPath Tutorial</title>
    <author>Mamun Zaman</author>
    <year>2007</year>
    <price>00.99</price>
  </book>
  <book>
    <title id='2'>AJAX Tutorial</title>
    <author>Charles</author>
    <year>2007</year>
    <price>03.45</price>
  </book>
</bookstore>

If the path starts with // then all elements in the document which fulfill the following criteria are selected. The //B expression selects all <B> tags regardless of their parents.

<root>
          <B/>
          <C/>
          <B/>
          <D>
               <B/>
          </D>
          <C>
               <D>
                    <B/>
                    <B/>
               </D>
          </C>
</root>

The star * selects all elements located by the preceding path. To select all elements under <book> use the /book/* path expression.

<bookstore>
  <book>
    <title id='1'>XPath Tutorial</title>
    <author>Mamun Zaman</author>
    <year>2007</year>
    <price>00.99</price>
  </book>
  <book>
    <title id='2'>AJAX Tutorial</title>
    <author>Charles</author>
    <year>2007</year>
    <price>03.45</price>
  </book>
</bookstore>